Dynamoelectric machine ventilating system



Feb. 5, 1946. 1. w. WIGHTMAN 2,394,414

DYNAMO- ELECTRIC MACHINE VENTILATING SYSTEM Filed May 11, 1945 Lawrance W. Wight-man,

, His Attorney.

Patented Feb. 5, 1946 DYNAMOELECTRIC MACHINE VENTILATIN G SYSTEM Lawrance W. Wightman, Fort Wayne, Ind., assignor to General Electric Company, a corporation of New York Application May 11, 1943, Serial No. 486,603

6 Claims.

My invention relates to ventilating systems and particularly to a ventilating system adapted to be used for cooling a dynamo-electric machine which may be subjected to wide variations in atmospheric pressure.

An object of my invention is to provide an improved ventilating system bailiing construction.

Another object of my invention is to provide a dynamo-electric machine having a ventilating system adapted to supply a substantially constant weight flow of ventilating medium through the machine.

Further objects and advantages of my invention will become apparent and my invention will be better understood from the following description referring to the accompanying drawing, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming part of this specification.

In the drawing, Fig. 1 is a side elevational view, partly broken away, of a dynamo-electric machine provided with an embodiment of my improved ventilating system; Fig. 2 is a partial sectional view of the end of a dynamo-electric machine illustrating another embodiment of my invention; Fig. 3 is a view of the construction shown in Fig. 2 taken along line 3-3; Figs. 4 and 5 show the relative positions of a pair of bailling plates shown in the construction of Figs. 6 and 7; Fig. 6 is a partial sectional view of a further embodiment of my invention; and Fig. 7 is an end view, partly broken away, showing the relative arrangement of the construction of Figs. 4, 5, and 6.

Referring to the drawing, I have shown in Fig. 1 an embodiment of my improved ventilating system applied to a dynamo-electric machine having a stationary member ID and a rotatable member provided with a commutator ll mounted on a shaft 12. The shaft I2 is supported by a bearing l3 mounted in a supporting .disk l4 formed with a plurality of axially extending ventilating openings l5 to provide for the passage of ventilating medium therethrough. A ventilating impeller fan It is provided with a supporting plate 38 mounted on the shaft 12 and is adapted to be driven thereby to provide for the circulation of ventilating medium through the machine by drawing air in through openings I! in an end shield ill at the opposite end of the machine and blowing this air out through openings I 8 in an end shield 20 mounted on a stationary member Ill of the machine. The imed on the inner side of the impeller blades and provided with a central opening 22 through which ventilating medium is adapted to pass. A baflie plate 23 is arranged in axially movable relationship relative to the fan supporting plate 38 axially spaced from the plate 2| and is supported by an annular pressure-responsive bellows member 24 which is secured at one end to the battle plate 23 and at the other end to a stationary support 25. The baffle plate 23 is formed with a cylindrical axially extending portion 26 having an opening therethrough arranged in communication with the central opening 22 of the plate 2|, and the cylindrical baflle portion 26 is adapted to extend through the opening 22 so as to direct ventilating medium passing from the dynamo-electric machine to the impeller fan It. The pressure-responsive bellows 24 is filled with a gas at a pressure such that the baflie plate 23 shuts off a portion of the intake opening to the impeller fan blades by the position of the cylindrical baiile portion 28 extending towards the outer side plate 38 of the impeller fan [6 when the bellows 24 is in its collapsed position under normal sea level atmospheric conditions. If the motor is used under atmospheric conditions such that the pressure about the machine is considerably reduced from sea level atmospheric pressure, the sealed bellows member 24 will expand and move the baflle plate 23 away from the same baflle plate 38 so as to vary the effective size of the ventilating medium opening between the baflling members by moving the cylindrical baiile portion 26 away from the outer side plate 38 of the impeller fan It, thereby increasing the size of the intake opening to the blades of the fan. In this manner, the efiective size of the ventilating medium opening through the bailling members is varied substantially inversely with the pressure around the machine, such that a substantially constant weight flow of ventilating medium through the machine is maintained. This is particularly desirable where such a machine is adapted to be used at varying altitudes, as it is not necessary to provide a large capacity machine at lowaltitudes in order to enable it to operate satisfactorily at higher altitudes and in a rarefied atmosphere when it is possible to provide for the dissipation of substantially the same heat under both conditions by providing for a more efiective use of the im peller fan on the machine. Furthermore, this also provides for a more eflicient operation of the machine by requiring the impeller fan l6 to peller fan construction includes a plate 2| mountdraw a smaller volume of air through the machine at higher atmospheric pressures and lower altitudes than would be the case if no provision were made to provide for a reduction of the ventilating medium drawn through the machine under these conditions as compared to those required for a higher altitude and lower atmospheric pressure condition.

In Figs. 2 and 3 I have shown another embodiment of my invention wherein the rotatable member shaft i2 is adapted to drive a ventilating impeller fan [6 for drawing air through the machine. In this construction, a baffle plate 21 is mounted on the shaft I2 and a relatively axially movable cooperating bailie plate 28 is supported on an annular pressure-responsive bellows mem ber 28 which is supported by a stationary plate 30 mounted in the stationary member end shield 20. In this construction under relatively high sea level atmospheric pressure about the machine, the annular supporting bellows member 28 is adapted to be substantially collapsed, and the relatively movable bafiles 21 and 2B are arranged to be substantially in radial alignment, such that very little ventilating medium may pass therebetween to the fan [6. If the atmospheric pressure surrounding the machine is decreased, the pressure of the gas in the bellows member 29 is adapted to expand the bellows and move the bafiie plate 28 to a position such as that shown in dotted lines away from the baiile plate 21, enlarging the size of the ventilating medium opening between the baffle plates. This operation of the battle plates by the supporting bellows member 29 provides for a variation in the size of the ventilating medium opening through the baiile members substantially inversely with the pressure about the machine in a'manner similar to that shown in Fig. 1.

In Figs. 4, 5, 6, and '7, I have shown another embodiment of my invention wherein the rotatable member shaft [2 of a dynamo-electric machine is adapted to drive a ventilating medium impeller fan 16 mounted thereon for drawing ventilating air through the machine. In this construction, a pair of relatively movable baifie plates 3i and 32 are mounted about the shaft l2 and are provided with a plurality of ventilating medium openings 33 and 34 arranged out of axial and circumferential registry. lhe baflle plate 3| is mounted in relatively axially movable relationship to the plate 32 and is supported by a plurality of pressure-responsive bellows members 35 which are mounted on the bafiie plate 32. These bellows members are filled with a fluid at a pressure such that under sea level atmospheric conditions, the bellows 35 are substantially collapsed and the bame plate 3| is supported as shown by dotted lines in Fig. 6. In this position, the efiective size of the ventilating medium opening through the two baille plates is relatively small, as indicated in Fig. 4, wherein the offset arrangement of the ventilating medium openings results in a net effective size 2.5. Under relatively low atmospheric pressure conditions about the machine, the fluid pressure within the bellows 35 causes the bellows to expand and move the bafile 31 away from the battle plate 32. so as to vary the relationship of the O enings 33 and 34 to vary the efiective size of the ventilatmg medium opening between the baffles, as shown in Fig. at 31. This arrangement provides for varying the effective size of the ventilating medium opening through the two baffie plates substantially inversely with respect to the pressure about the machine in a manner similar to that shown by the constructions of Figs. 1 to 3 with corresponding advantages.

While I have illustrated and described particular embodiments of my invention, modifications thereof will occur to those skilled in the art. I desire it to be understood, therefore, that my invention is not to be limited to the particular arrangements disclosed, and I intend in the appended claims to cover all modifications which do not depart from the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent in the United States is:

1. A dynamo-electric machine having a stationary member and a rotatable member provided with a ventilating system construction including a ventilating medium impeller arranged to be driven by said rotatable member, a bathing member mounted on said stationary member and having an opening therein, a relatively movable baffling member having an opening therein for varying the flow of ventilating medium through said impeller, and pressure-responsive means for movably supporting said relatively movable baifling member in axially movable relationship to said first-mentioned bafliing member for varying the effective size of the ventilating medium opening through said bafiling members substantially inversely with the pressure around said machine maintaining a substantially constant weight flow of ventilating medium through the machine.

2. A dynammelectric machine having a stationary member and a rotatable member provided with a ventilating system construction including a bafiiing member having an opening therein and mounted on said stationary member, a. relatively movable baflling member having an opening therein for varying the flow of ventilating medium through the machine, and pressureresponsive means for movably supporting said relatively movable baffling member in axially movable relationship to said first-mentioned baifling member for varying the efiective size of the ventilating medium opening through said baming members substantially inversely with the pressure around said machine maintaining a substantially constant weight flow of ventilating medium through the machine.

3. A dynamo-electric machine having a stationary member and a rotatable member provided with a ventilating system construction including a ventilating medium impeller arranged to be driven by said rotatablemember, a baflling member mounted on said stationary member and having an opening therein, a relatively movable bathing member having an opening therein for varying the fiow of ventilating medium through said impeller, and means including a pressure responsive member for supporting said relatively movable baffling member in axially movable relationship to said first-mentioned bafiiing member for varying the eiIective size of the ventilating medium opening through said battling members substantially inversely with the pressure around said machine maintaining a substantially constant weight flow of ventilating medium through the machine.

4. A dynamo-electric machine having a stationary member and a rotatable member provided with a ventilating system construction provided with a bailiing member having an opening therein mounted on said stationa y member, a. relatively movable bafliing member arranged to close off part or said first-mentioned battling member opening and having an opening therein arranged to provide communication through said first-mentioned bailling member opening for varying the flow of ventilating medium through the machine, and pressure-responsive means for varying the relationship of said openings in said bafiling members to vary the effective size of the ventilating medium opening therebetween substantially inversely with respect to the pressure around said machine maintaining a substantially constant weight flow of ventilating medium through the machine.-

5. A dynamo-electric machine having a stationary member and a rotatable member provided with a ventilating system construction provided with a ventilating medium impeller arranged to be driven by said rotatable member, a relatively stationary baiilling member having an opening therein mounted on said stationary member, a relatively movable bailling member having an opening therein for varying the flow of ventilating medium through said impeller, and means including a pressure-responsive bellows member for supporting said movable baffling member in axially movable relationship to said stationary baffling member for varying the relationship of said openings in said baffling members to vary the effective size or the ventilating medium opening therethrough substantially inversely with respect to the pressure around said machine maintaining a substantially constant weight flow of ventilating medium through the machine.

6. A ventilating system bafiling construction including a casing, a baflling member arranged transversely of said casing, a relatively movable baflling member having an opening therein and arranged transversely of said casing and axially movable therein, and an annular pressure responsive means with a central opening therein substantially in alignment with the opening in said movable bailiing member for passage of fluid through said openings and providing the only positioning means for said relatively movable baflling member for supporting said movable baffling member and varying the relative position of said bailiing members to vary the effective size of the ventilating medium opening therebetween substantially inversely with the pressure around said pressure responsive means and said baflling member.

LAWRANCE W. WIGH'I'MAN. 

